This invention relates to semiconductor processing, and, in particular, to methods and apparatus for etching materials on a substrate.
Various structures and devices are created during the fabrication of logic and memory microchips. For example, transistors, such as field effect transistors, or basic elements of microelectronics and integrated circuits. Fabricating such transistors generally involves depositing layers of various materials, patterning layers, transferring patterns, and removing materials. A common technique for pattern transfer is using a plasma-based etching process, also known as a dry etching process. Such etch-based pattern transfer typically involves a topographic pattern that functions as a mask so that etchants directed toward the substrate etch material in exposed portions of an underlying layer, while the mask prevents etching covered portions of the underlying layer.